A phenolic hydroxy group-containing compound is not only used for an adhesive, a molding material, a coating material, a photoresist material, an epoxy resin raw material, or a curing agent for an epoxy resin, but is also widely used in the electric and/or electronic field such as a semiconductor sealing material or an insulating material for a printed circuit board, as a curable resin composition using the phenolic hydroxyl group-containing compound itself as a main agent, or as a curing agent of an epoxy resin, since a cured product has excellent heat resistance and moisture resistance.
Among these, as a resin material for a positive-type photoresist, a resin composition has been widely used, which is composed of a novolak type phenolic resin having excellent heat resistance and alkali solubility and a photosensitizer such as a naphthoquinone diazide compound. However, in recent years, as a circuit pattern has become more detailed, improvement of optical sensitivity and resolution is further required, and development of a new resin material for a photoresist is expected.
As the new photoresist material having excellent optical sensitivity and resolution, a chemically amplified photoresist has been highlighted. The chemically amplified photoresist is composed of a photoacid generator and a resin material whose alkali solubility is greatly changed under the condition of an acid catalyst, and in the case of a positive-type photoresist, a resin material, which changes from alkali-insoluble to alkali-soluble as a result of generation of an acid upon irradiation with light, is used. As the resin material for this chemically amplified photoresist, for example, a modified cresol novolak resin, in which an acid dissociable protective group is introduced to a part or the entirety of phenolic hydroxy groups of a cresol novolak type resin, is known (for example, refer to PTL 1). The chemically amplified photoresist material using the modified cresol novolak resin, and disclosed in PTL 1 has excellent optical sensitivity or resolution, compared to the conventional type photoresist material; however, the optical sensitivity and resolution are not sufficient in order to form a more detailed pattern, and as a result of modifying the phenolic hydroxy group, heat resistance or moisture absorption resistance of a coating is remarkably decreased.